Workpiece Positioning Using Keyed Impressions and Optical Scanning
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Solution Overview
Problem
The precise positioning of workpieces in machine tools is complex and time-consuming due to the lack of accurate mapping between the design coordinate system and the machine tool coordinate system, especially in dental prosthesis production where temperature-sensitive mechanical measuring probes are costly and require significant calibration and space, and existing methods lack precision and efficiency.
Innovation Solution
A method using a duplicate workpiece with key structures and a counter to establish precise positioning, allowing the workpiece to be reproducibly aligned in the machine tool, enabling accurate machining by converting design data into tool coordinates, and utilizing mobile intraoral scanners for higher precision and temperature independence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical measuring probes are used for positioning, then positioning can be achieved, but the system becomes temperature-sensitive, complex, and expensive
Solution Approach 1:
The patent replaces mechanical measuring probes with an optical scanning system (intraoral scanner) to capture geometric data of the workpiece. The scanner creates a point cloud that is processed into a coordinate system, eliminating the need for complex mechanical probe systems while achieving comparable or superior positioning precision without temperature sensitivity.
2Measurement precision
If mechanical measuring probes are used for positioning, then positioning can be achieved, but calibration and space requirements increase
Solution Approach 1:
The patent performs preliminary scanning of the workpiece to create a digital model and coordinate system before machining begins. This preliminary action captures all necessary geometric information upfront, eliminating the need for repeated calibration during the machining process and reducing overall time loss.
3Manufacturing precision
If precise positioning is achieved through traditional methods, then machining accuracy can be maintained, but the process becomes time-consuming and complex
Solution Approach 1:
The patent replaces time-consuming mechanical positioning and calibration procedures with rapid optical scanning and automated coordinate system generation. The scanner quickly captures workpiece geometry, and software automatically processes the data into usable coordinates, dramatically reducing positioning time while maintaining high machining accuracy.
Solution Approach 2:
The patent changes the fundamental parameter of positioning from mechanical contact-based measurement to optical non-contact scanning. This parameter change enables faster data acquisition and processing, improving productivity while maintaining the precision needed for accurate machining operations.
4Manufacturing precision
If coordinate system mapping is performed traditionally, then machine tool positioning can be achieved, but the mapping process is complex and error-prone
Solution Approach 1:
The patent replaces complex manual or mechanical coordinate mapping procedures with automated optical scanning and software-based coordinate system generation. The scanner captures geometric features, and algorithms automatically establish the coordinate system and map it to the machine tool, reducing human error and simplifying the process.
Data Source
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AI summary
In an embodiment of the method for the precise positioning of a workpiece, especially a dental prosthesis (1), in a machine tool an impression is made on a part that can be precisely positioned relative to the machine tool, said impression likewise having a known position, in order to be able to position the workpiece precisely on the impression and thus in the machine tool for processing. A corresponding apparatus comprises a blank (3) and a mating piece or counter-piece (25) on which an impression (20) is made. Blank and counter-piece have key structures (9, 10; 21, 22) which allow separation and reproducible reconnection of blank and counter-piece relative each other in the same arrangement. A calculation-based alternative is to provide the workpiece with reference elements (41), determining their positions by scanning the workpiece (1), processing steps being produced on the basis of the scan, and scanning, in a machine tool, the (prepared) workpiece on a blank having key structures (9, 10) the machine tool coordinates of which are known, in order to determine the position of the workpiece in the machine tool both in terms of machine tool coordinates as well as construction system coordinates.